Instrument for fine-mechanical or surgical applications

ABSTRACT

The invention relates to an instrument for high-precision or surgical applications of a minimally invasive nature, comprising a distally positioned directable head, a shaft upon which the head is positioned, and a proximally positioned handgrip for operating the head, wherein a ring of cables comprising longitudinally extending cables connects to the head, wherein each cable of the ring of cables is disposed such that at least a part of both sides is in direct contact with another cable of the ring of cables, and wherein the cables are fixedly secured in the radial direction.

The invention relates to an instrument for high-precision or surgicalapplications of a minimally invasive nature, comprising a distallypositioned directable head, a rigid, flexible, or semi-flexible shaftupon which the head is positioned, and a proximal end equipped foroperating the head. This proximal end may be provided with, or example,a handgrip or a control (possibly motor-powered). In the latter case,this may also entail a computerised control. The high-precisionapplications include, for example, the inspection and repair of motors,machines, radiators or tubular systems.

Such an instrument is known for medical applications from, among others,the international patent application PCT/NL01/00552, published under no.WO 02/13682.

From this publication an endoscope is known, embodied with a distallypositioned camera, fitted on an endoscope shaft, wherein proximallypositioned means are provided for operating the camera. To realise thecoupling or the operating means and the camera, use is made of a spring,which is comprised of a chain of in themselves closed, flexible elementswherein the elements or each pair of two adjacent elements as comprisedin this chain are only partially connected with each other. Throughthese mutually connected elements traction wires are threaded throughfeed-through openings that are provided in the elements.

The known construction has several drawbacks. These drawbacks concernthe fact that there is a limit to how small the elements forming thespring can be while still keeping the spring at a desirably low costprice. Another drawback is that when the camera is set at an angle tothe shaft, the four traction wires used in the known constructionestablish referred positions.

An object of the invention is to eliminate these problems and to allowthe medical instrument to be constructed at low costs.

Corresponding to the preamble of claim 1, an instrument of the kindexplained above is known from US-A-2002/0177750, wherein a ring ofcables comprising longitudinally extending cables connects to the head,which cables are fixedly secured in the radial direction. A disadvantageof this instrument is, however, that the cables are fed throughguide-sleeves provided in the longitudinal direction of the cables andattached to an externally extending leaf spring. This construction iscomplex and expensive.

The instrument according to the invention is characterized in that eachcable of the ring of cables is disposed such that at least a part ofboth sides is in direct contact with another cable of the ring ofcables.

This instrument lends itself especially for surgical applications, aswill become apparent from the following explanation. Of course,high-precision applications are equally well possible, and may bederived without inventive effort from the explanation given hereinbelow.It should be noted that other longitudinally extending elements, withwhich a closed ring can be formed, also fall within the scope of theterm “cable” used in the invention. This relates, for example, to a ringof (hollow) tubes, or glass fibres to be mentioned hereinbelow.Similarly, it is not necessary for all of the cables to have the samedimensions. For example, cables having a completely round cross-sectionmay be disposed next to cables having a banana-shaped cross-section.

The instrument according to the invention can be manufactured atexceptionally low costs since the cables may be thin steel cables of thekind normally available on the market. Such steel cables are availablewith a diameter of, for example, 0.2 mm. This means that if a centralchannel de-limiting the ring of cables has a diameter of 0.2 mm, it ispossible to manufacture a ring of cables having a minimum diameter of0.6 mm. It is thus possible to realise a shaft diameter having adiameter of approximately 1 mm.

An essential aspect or the invention is that in the radial andtangential direction, the cables of the ring of cables are fixedlysecured. Preferably, the cables comprising the ring of cables are overtheir whole length in direct contact with neighbouring cables. Thisenables the cables of the ring of cables to absorb a pulling force aswell as a pushing force, allowing the ring of cables to be used for themechanical coupling of the head to a handgrip.

An important advantage of the instrument according to the invention isfurther that the same is without preferred positions with respect to themovement of the head in relation to the shaft.

For the mechanical coupling of the head to the handgrip any cable fromthe ring of cables may be employed. In a preferred embodiment, however,the instrument according to the invention is characterized in that theends of at least some of the cables of the ring of cables possess afastening to the head and to the proximal end. In this way the fasteningcan be constructed in a simple and consequently cheap manner, forexample, by means of soldered connections or by using bolts provided inan endplate wherein the ends of the cables having a pulling function canbe received.

An embodiment that is preferred when all of the cables provide themechanical coupling for the head to the handgrip, is characterized inthat the fastening is embodied as an interior ring and an exterior ring,which together delimit a slot for clampingly receiving the cables. Thisconstruction can also be used if only some of the cables of the ring orcables are received in the slot.

A simple and inexpensive embodiment of, the instrument according to theinvention for the fixedly securing the ring of cables is characterizedin that the ring of cables is enclosed by an exterior spring lyingagainst the cables of the ring of cables.

It is also possible for the ring of cables to be provided at itsexterior side with a construction element selected from the groupcomprising glass fibres, cables, power cables, power cables surroundedby glass fibres, an optionally torsion-stiff tube or tubes, optionallywith lateral scoring and optionally stranded, a bellows, a stent and aspring as specified in WO 02/13682.

For the internal retention of the ring of cables numerous technicalpossibilities can be used. For example, a simple and effectivepossibility is to be found in the embodiment wherein the ring of cablesis provided at its interior side with an interior spring lying againstthe cables of the ring of cables.

It is also possible for the ring of cables to be provided at itsinterior side with a construction element that is selected from thegroup comprising a bundle of glass fibres, a cable, power cables, apower cable surrounded by a ring of glass fibres, an optionallytorsion-stiff tube or tubes, optionally with lateral scoring andoptionally stranded, bellows, a stent and a spring as specified in WO02/13682.

It is also conceivable that the construction element selected from thisgroup is used in combination with an internal spring lying against thecables of the ring of cables. If such an internal spring is not used,the selected construction element itself must lie against the cables ofthe ring of cables.

If the construction element is a cable, it is advantageous that on thehead of the instrument a grab jaw, scissors or clipping tongs be mountedand the cable be embodied as control cable therefor. This is especiallyuseful for medical applications.

However, if the construction element comprises a power cable, it isadvantageous for the instrument to be embodied with a camera mounted onthe head, wherein the power cable serves for the power supply of saidcamera and/or for transporting image data obtained with the camera. Ofcourse, it is also possible to use several power cables having separatefunctions. In addition, the power cable or power cables may serve forfeeding a light source, such as an LED or the like. Glass fibres arealso useful as light conductors, while they are at the same time able toserve as traction rope.

The instrument proposed in accordance with the invention, is preferablyselected from the group comprising laparoscope, thoracoscope,colonoscope, gastroscoie, bronchoscope, endoscope, catheter, surgicaldrill, uretheroscope, laryngoscope, cystoscope, guidable endoscope,guidable drill, gripping tongs, clipping tongs, scissors, coagulationhook, and generally instruments for ear, nose and throat surgery, eyesurgery, neurosurgery and brain surgery.

Hereinbelow the invention will be further elucidated by way of thedrawing.

In the drawing:

FIG. 1 a shows a cut-away drawing of substantially the head of theinstrument according to the invention;

FIG. 1 b shows a detail of a preferred embodiment of the fastening ofthe ring of cables;

FIGS. 2 a and 2 b show a longitudinal cross-section of an instrumentaccording to the invention in the straight and bent condition,respectively;

FIG. 3 shows a longitudinal cross-section or an alternative embodimentof the construction of the instrument according to the invention shownin FIGS. 2 a and 2 b;

FIG. 4 shows several alternative constructions for internally securingthe ring of cables forming part of the instrument according to theinvention.

FIGS. 5 a and 5 b show several alternative fastenings of the cables ofthe ring of cables, to be used at the head and/or the proximal end ofthe instrument according to the invention.

Similar components in the figures carry identical reference numerals.

With reference first to FIGS. 2 a and 2 b, showing the main portion of amedical instrument selected from the group comprising laparoscope,thoracoscope, colonoscope, gastroscope, bronchoscope, endoscope,catheter, surgical drill, uretheroscope, laryngoscope, cystoscope,guidable endoscope, guidable drill, gripping tongs, clipping tongs,scissors, coagulation hook, instruments for ear, nose and throatsurgery, eye surgery, neurosurgery and brain surgery.

Comparison between the FIGS. 2 a and 2 b shows clearly that theinstrument 1 possesses a distally positioned directable head 2, a shaft3 on which a head 2 is positioned and a proximal end on which in thiscase a handgrip 4 is positioned that serves for controlling the head 2.

Depending on the desired application, the head 2 may be provided, forexample, with a grab jaw or a camera, as will be explained hereinbelow.

A detail of the instrument 1 near the head 2 is shown in the FIGS. 1 aand 1 b.

FIG. 1 a shows the shaft 3 and the head 2 positioned on the shaft 3 intwo separate longitudinally extending halves. This illustrates that inthis example shown, the shaft 3 possesses a shaft wall wherein a ring ofcables 5 is contained that comprises cables 6 extending longitudinallyin the shaft 3, as indicated with regard to a number of these cables inFIG. 1 a. From FIG. 1 a it is further clearly apparent that in theradial direction each cable 6 of the ring of cables 5 is fixedlysecured. To this effect, the construction shown in FIG. 1 a is providedwith an external spring 7 disposed up against the cables 6 of the ringof cables 5 and an internal spring 8 lying against the interior side ofthe ring of cables 5 up against the cables 6 of the ring of cables 5.

The ring or cables 5 serves for the mechanical coupling of the head 2with the handgrip 4 (see FIGS. 2 a and 2 b).

FIG. 1 b shows an exploded view of a means for realising a fastening 9of cables 6 of the ring of cables 5 to the head 2 and the handgrip 4,respectively. The fastening 9 shown in FIG. 1 b comprises an interiorring 10 and an exterior ring 11, which together delimit a slot 12serving to clampingly receive the cables 6 of the ring of cables 5. Asalready mentioned in the introduction of this exemplary embodiment, thismay, for example, be realised such that only every other cable 6 isreceived in the slot 12. In such a case other fastenings 9 are alsofeasible. Some non-limiting examples are shown in FIGS. 5 a and 5 b.

FIG. 5 a shows the fastening 9 wherein the ends of every other cable 6′may be received in an endplate 13 in order to be fixed therein withsoldering points 14. Between these fixed cables 6′ run so-calledfloating cables 6″.

FIG. 5 b shows the construction in which ends of the cables 6′ arereceived in an endplate 13 in order to be fixed therein with bolts 15.

With respect to the interior spring 8 serving to secure the cables 6 ofthe ring of cables 5 at the inside, alternative embodiments are alsoconceivable. FIG. 4, on the right, shows an embodiment in which thecables 6 of the ring of cables are internally delimited by a cable 16.This may be, for example, a traction rope, which serves to operate agrab jaw to be mounted on the head 2 of the instrument 1. In thatembodiment, the traction rope 16 is able to undergo a longitudinalmovement in relation to the adjacent cables 6 of the ring of cables 5.In a manner known to the person skilled in the art, the grab jaw may beequipped with a spring element to produce a counter-force to the forceto be exerted by means of the traction rope 16, such that the grab jawcan be both opened and closed, depending on the position of the tractionrope 16. It should be noted, that in the construction illustrated thetraction rope 16 may also be used as pushing rope, so that the saidspring element may be omitted. Since a person skilled in the art isacquainted with the character of such a grab jaw, a further constructiveexplanation is superfluous and is therefore omitted.

FIG. 4 on the left, shows an embodiment of the instrument according tothe invention wherein the traction rope 16 extends in the interior of aninterior spring 8, which together with the exterior spring 7 ensuresthat the cables 6 of the ring of cables 5 are fixedly secured.

Apart from the just explained embodiment in which a traction rope 16extends at the inside of the ring or cables 5, it is also possible toprovide a power cable or power cables, or a power cable surrounded by aring of glass fibres, or a tube or even a spring as specified in WO02/13682. Another possibility is the application or a stent. Each of theabove-mentioned possibilities has its advantages, which may be selectedin accordance with the intended application. For example, the embodimentusing the stent or using the spring known from WO 02/13682, possessesgreater torsion rigidity in comparison with the embodiment using aninternal spring.

The embodiment in which the construction element is a power cable, mayadvantageously be embodied with a camera mounted on the head 2, whereinthe power cable, in a manner known to the person skilled in the art,serves to feed the camera and wherein said same cable or more additionalpower cables can be used for the transport of image data. It is alsopossible to use glass fibres, which are preferably applied in a ringaround the power cable for conducting light for the image data to berecorded with the camera. The person skilled in the art is quitefamiliar with the manner in which this is to be accomplished, so thatthere is no need for further explanation.

With regard to the directability of the head 2, the working principle ofthe instrument 1 according to the invention may be explained quitesimply by referring to the FIGS. 2 a and 2 b.

It is, for example, possible to fasten a miniature camera to the head 2,with a feed cable for the camera and glass fibres for the conduction oflight through the interior of the interior spring 8. The cables 6 of thering of cables 5 are fixed with a fastening 9, which at the head sidesurrounds the interior ring 10 discussed with reference to FIG. 1 b andthe exterior ring 11. A similar construction is provided at the side ofthe handgrip 4. The fastening 9 is at the side of the handgrip 4slidably accommodated therein.

The illustrated instrument 1 comprises four helical springs, i.e. acompression spring 17 directly behind the head 2, a draw spring 18between shaft 3 and handgrip 4, a compensation spring 19 accommodated inthe handgrip 4 and an interior spring 8 extending over the total lengthof the instrument 1. It should be noted that in the (straight) shaft 3,the interior spring 8 may be substituted by a tube.

The springs have the following functions:

The draw spring 18 is embodied as closed draw spring so that the same isrelatively rigid with respect to movements other than the desiredbending movement. Along a portion of the circumference, the draws spring18 is preferably glued to the shaft 3 or the handgrip 4, respectively,in order to increase the torsion rigidity of the construction.

The interior spring 8 is a weak spring whose function is to keep thecables 6 of the ring of cables 5 in position.

The function of the compensation spring 19 is to in the straightcondition compress the spring 17 positioned behind the head 2 until thesame is closed. To this end the compensation spring 19 is slightlyheavier than the compression spring 17.

The instrument 1 works as follows: bending the handgrip 4 causes theportion of the lower cables 6 off the ring of cables 5 indicated witharrow A to elongate. Because the portion of said cables 6 indicated witharrow B is unable to shorten due to the spring 17 being in the straightcondition completely closed, the cables 6 in the portion of cables 6indicated with C are caused to shorten. This makes the fastening rings 9in the handgrip 4 move in the direction of the distal end while theupper cables 6 are paid out to give the compression spring 17 room tobend over a same angle as draw spring 18 does as a result of thehandgrip 4 being moved.

FIG. 3 finally shows a schematic illustration of an embodiment of themedical instrument 1 according to the invention, wherein shecompensation spring 19 shown in FIGS. 2 a and 2 b in the handgrip 4 isomitted. When the handgrip 4 is being moved, the necessary length of thecables 6 must then be made available through compression of the spring17 located behind the head 2, to which end the spring 17 must not beclosed in the straight condition.

The study that resulted in the present invention was made possible by agrant from the Royal Dutch Academy of Sciences.

The invention claimed is:
 1. An instrument for high-precision orsurgical applications of a minimally invasive nature, comprising: ashaft defining a longitudinal axis and a radial direction perpendicularto the longitudinal axis; and a deflectable head positioned on a distalend of the shaft, wherein the shaft includes a proximal end equipped fordirecting the deflectable head, wherein the shaft is provided with afirst construction element arranged internal to a ring of cables and asecond construction element arranged external to said ring of cablescomprising cables extending in a longitudinal direction of the shaft,the cables connected to the deflectable head and to the proximal end,wherein the cables are fixedly secured by said first and secondconstruction elements in the shaft's radial direction and are movable inthe shaft's longitudinal direction, and wherein each cable of the ringof cables is disposed such that at least a part of both sides of thecable is in direct contact with another cable of the ring of cables andextends parallel to the longitudinal direction of the shaft, and suchthat the ring of cables transmits a force from the proximal end to thedeflectable head, which force causes the deflectable head to bemanipulated from a position in which the deflectable head is alignedwith the longitudinal axis of the shaft to a position in which thedeflectable head is deflectable from the longitudinal axis of the shaft.2. An instrument according to claim 1, wherein: a handgrip is positionedon the proximal end of the shaft; and the ring of cables is designed formechanically coupling the deflectable head to the handgrip.
 3. Aninstrument according to claim 2, wherein ends of at least some of thecables of the ring of cables possess a fastening to the deflectable headand to the proximal end.
 4. An instrument according to claim 3, whereinthe fastening is embodied as an interior ring and an exterior ring,which together delimit a slot for clampingly receiving the cables.
 5. Aninstrument according to claim 1, wherein the second construction elementis an exterior spring lying against the cables of the ring of cables. 6.An instrument according to claim 1, wherein the second constructionelement is provided external to the ring of cables, the secondconstruction element selected from the group consisting of glass fibres,cables, power cables, power cables surrounded by glass fibres, a tube ortubes, bellows, a stent and a spring.
 7. An instrument according toclaim 1, wherein the first construction element is an interior springprovided internal to the ring of cables, the interior spring lyingagainst the cables of the ring of cables.
 8. An instrument according toclaim 1, wherein the first construction element is provided internal tothe ring of cables, wherein the first construction element is selectedfrom the group consisting of a bundle of glass fibres, a cable, a powercables, a power cable surrounded by a ring of glass fibres, a tube ortubes, bellow, a stent and a spring.
 9. An instrument according to claim8, wherein the first construction element lies against the cables of thering of cables.
 10. An instrument according to claim 8, wherein thefirst construction element is a cable, wherein on the deflectable head agrab jaw, scissors or clipping tongs is mounted and the cable isembodied as control cable therefor.
 11. An instrument according to claim8, wherein the first construction element comprises at least one powercable, wherein a camera is mounted on the deflectable head and the powercable serves for the power supply of the camera and/or for transportingimage data obtained with the camera.
 12. An instrument according toclaim 1, wherein the instrument is selected from the group comprisinglaparoscope, thoracoscope, colonoscope, gastroscope, bronchoscope,endoscope, catheter, surgical drill, uretheroscope, laryngoscope,cystoscope, guidable endoscope, guidable drill, gripping tongs, clippingtongs, scissors, coagulation hook, and generally instruments for ear,nose and throat surgery, eye surgery, neurosurgery and brain surgery.13. An instrument according to claim 6, wherein the second constructionelement lies against the cables of the ring of cables.
 14. An instrumentaccording to claim 6, wherein the second construction element is acable, wherein on the head a grab jaw, scissors or clipping tongs ismounted and the cable is embodied as control cable therefor.
 15. Aninstrument according to claim 6, wherein the second construction elementcomprises at least on power cable, wherein a camera is mounted on thehead and the power cable serves for the power supply of the cameraand/or for transporting image data obtained with the camera.